IBM pSeries - Manual (Page 19)

pshpstuningguidewp040105.doc Page 19
5.0 Debug settings and data collection tools
Several debug settings and data collection tools can help you debug a performance problem on
systems using HPS. This section contains a subset of the most common setting changes and
tools. If a performance problem persists after you check the debug settings and the data that was
collected, call IBM service for assistance.
5.1 lsattr tuning
The lsattr command lists two trace and debug-level settings for the HPS links. The following
settings are recommended for peak performance and are the defaults.
Parameter Setting
driver_debug 0
ip_trc_lvl 0x1111
5.1.1 driver_debug setting
The driver_debug setting is used to increase the amount of information collected by the HPS
device drivers. eave this setting set to default value unless you are directed to change it by IBM
service.
5.1.2 ip_trc_lvl setting
The ip_trc_lvl setting is used to change the amount of data collected by the IP driver. Leave this
setting set to default value unless you are directed to change it by IBM service.
5.2 CPUs and frequency
Performance of parallel application can be impacted by the number of CPUs on an LPAR and by
the speed of the processors. To see how many CPUs are available and the frequency they run at,
run any of the following commands:
lsdev -Cc processor
lsattr -E -l proc#
bindprocessor -q
prtconf
pmcycles –m
If you mix slow CPUs and fast CPUs within a parallel job, the slowest CPU determines the speed
for the entire job.